All ETDs from UAB

Advisory Committee Chair

Clinton Lothrop

Advisory Committee Members

Xu Feng

Christopher Klug

Thomas Ryan

Gene P Siegal

Document Type

Dissertation

Date of Award

2013

Degree Name by School

Doctor of Philosophy (PhD) Heersink School of Medicine

Abstract

Mutations in the AP3-ß1 gene are known to cause Hermansky-Pudlak syndrome type 2 (HPS2) in humans and canine cyclic hematopoiesis (CH) in gray collie dogs. HPS2 patients have severe congenital neutropenia (SCN), and dogs have cyclic neutropenia (CN). The mechanism behind neutropenia is uncertain. Pearl mice have an AP3-ß1 mutation, but whether they actually have neutropenia has not yet been evaluated. This dissertation presents a discussion of the evaluation of neutropenia in pearl mice, hematopoietic progenitor cell mobilization defect in pearl mice and finally an evaluation of methods of dog-to-mouse xenotransplantation to establish a xenotransplant model of the dog hematopoietic system. Dog xenotransplant models could be used to model canine CN. Based on complete blood counts as part of this dissertation research, Pearl mice do not have SCN or CN. The number of colony forming units (CFU) that form colonies containing granulocytes and bone marrow lineage negative (lin-), Sca+ and c-kit+ cells in the bone marrow were, in fact, shown to be moderately increased in pearl mice. Normal and pearl mice also had similar responses to cyclophosphamide and bortezomib. AMD3100 treatment resulted in similar numbers of peripheral blood CFUs and CBCs in Bl/6 and pearl mice. However, Bl/6 mice administered G-CSF had higher peripheral blood neutrophil counts and greater peripheral blood CFU numbers than pearl mice. Pearl mice did have decreased hematopoietic progenitor cell/granulocyte mobilization in response to G-CSF. Additional studies will be necessary to determine if CH dogs or HPS2 patients also have a mobilization defect. Dog-to-NSG mouse xenotransplant models could aid in the study of neutropenia in dogs. Four methods of cell delivery that have been used in human xenotransplant studies were tested: Tail-vein injections, intrafemoral injections, intrafemoral injections after flushing the femur, and neonatal liver injections. Mice that stably engrafted developed severe graft vs. host disease. Further studies are necessary to determine pre- and post-transplant conditions that will allow for improved survival and engraftment. Establishment of an optimal dog-to-mouse xenotransplant protocol will aid in the study of neutropenia in the CH dog. It will also allow for opportunities to establish dog xenotransplant models of other diseases.

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